Design of experimental food patches to measure foraging intensity for octopus: a case study with the giant Pacific octopus Enteroctopus dofleini

2020 ◽  
Author(s):  
Stephanie Chancellor ◽  
David Scheel ◽  
Joel S Brown
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Habitat Preferences ◽  
High Tide ◽  
Intertidal Habitat ◽  
Camera System ◽  
Subtidal Habitat ◽  
Enteroctopus Dofleini ◽  
Nontarget Species

ABSTRACT In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

Modification of 0+ perch foraging behaviour by indirect cues of predation risk

2006 ◽  
Vol 15 (2) ◽  
pp. 118-124 ◽  
Author(s):  
J. Wanzenbock ◽  
V. N. Mikheev ◽  
A. F. Pasternak
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Indirect Cues

Predation risk and distance to cover affect foraging behaviour in Namib Desert gerbils

1993 ◽  
Vol 46 (6) ◽  
pp. 1243-1245 ◽  
Author(s):  
Jessica J. Hughes ◽  
David Ward
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Namib Desert

Extreme waves and surges interaction with tides during storms in winter 2013/2014.

2021 ◽  
Author(s):  
Julia Rulent
Keyword(s):  
Tidal Cycle ◽  
Grid Point ◽  
High Tide ◽  
Water Levels ◽  
Extreme Waves ◽  
Near Shore ◽  
The Uk ◽  
The Waves ◽  
Tidal Stage

<p>The interaction between waves, surges and tides is one of the main drivers of coastal total water levels (TWL).  Understanding this interaction is crucial for studying high TWL formation near shore, and to do this it is important to not only evaluate how high the TWL is but also when and where it occurs.</p><p>In this study we use a high resolution (1.5 km) three-way coupled (waves-atmosphere-ocean) numerical model developed by the MetOffice (UKC4) to study coastal conditions at the UK coast during the extreme events of winter 2013, which was chosen as case study because of the amount of flooding that occurred in relation to storms and surges during this period.</p><p>For each coastal grid point the ten strongest storms of that winter, ranked by the significant wave height (Hs) magnitude, were selected. During these storm periods, the number of hours in which Hs and surges exceeded the 90<sup>th</sup> percentile of winter 2013 were evaluated considering what tidal stage they occurred on. The same was done for instances where high Hs and surges occurred simultaneously. The aim is to understand if specific areas were predominantly affected by one of the TWL components and how Hs and surges interacted with the tide. What was the spatial distribution of the waves, surges, and tides during winter 2013? Did extreme Hs and Surges occur more often over specific stages of the tidal cycle? Did they occur simultaneously? </p><p>In this study we show that during the winter 2013, Hs and surges above the 90<sup>th</sup> percentile value did occur simultaneously at all stages of the tidal cycle. They more often occurred together over the rising tide with in average 8.7% and 8.6% of instances found two and three hours before high tide. In 7.7% of cases high wave and surges also concurred at high tide.</p>

GICS IN THE MAIN TRANSMISSION LINE “NORTHERN TRANSIT” IN RUSSIA AND IN THE MÄNTSÄLÄ FINLAND PIPELINE: A CASE STUDY

2021 ◽  
Vol 44 ◽  
pp. 20-23
Author(s):  
I.V. Despirak ◽  
◽  
P.V. Setsko ◽  
Ya.A. Sakharov ◽  
V.N. Selivanov ◽  
...  
Keyword(s):  
Negative Impact ◽  
Temporal Structure ◽  
Auroral Zone ◽  
Magnetic Data ◽  
Geomagnetically Induced Currents ◽  
Camera System ◽  
Natural Gas Pipeline ◽  
Spatio Temporal ◽  
Using Data

Geomagnetically induced currents (GICs), arising both on power lines and on pipelines, may have strong negative impact on the technological networks up to accidents ("blackouts"). Magnetospheric disturbances are one of the factors in the appearance of GICs, however there is no unambiguous relationship between substorm and presence of currents. In this paper, we consider two intense cases of GIC (15March 2012 and 17 March 2013), registered on two different technological networks: 1) on the "Nothern Transit" power line (Vykhodnoy, Revda and Kondopoga stations) located in the auroral zone, 2) on the Finnish natural gas pipeline near Mäntsälä located in the subauroral zone. Both GIC cases are compared with substorm development in the auroral zone, using data from IMAGE magnetometers network and MAIN camera system in Apatity. We found a good correlation between the GIC appearance and variations of geomagnetic indexes: IL – index, which characterized of westward electrojet intensity on the IMAGE meridian and Wp - index, which describes the wave activity of the substorm. Besides, it was shown also a good correlation between GICs and the thin spatio-temporal structure of the substorm development (the appearance and the propagation to the pole of substorm activations), which is appeared both in the magnetic data and in the all sky camera images.

Are polymorphic species of Uropodina (Acari: Mesostigmata) more successful evolutionarily?—A case study of closely related species from the genus Oodinychus Berlese, 1917 based on DNA sequences

2019 ◽  
Vol 24 (5) ◽  
pp. 866
Author(s):  
Jerzy Błoszyk ◽  
Katarzyna Buczkowska ◽  
Anna Maria Bobowicz ◽  
Alina Bączkiewicz ◽  
Zbigniew Adamski ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Related Species ◽  
Habitat Preferences ◽  
Abundant Species ◽  
Systematic Position ◽  
Genetic Differences ◽  
Similar Species ◽  
Closely Related Species ◽  
Wide Range

The study presented in this research paper is the first taxonomic investigation focusing on Uropodina (Acari: Mesostigmata) mites with a brief discussion of the genetic differences of two very closely related species from the genus Oodinychus Berlese, 1917, i.e. O. ovalis (C.L. Koch, 1839) and O. karawaiewi (Berlese, 1903). These two morphologically similar species are quite common and they have a wide range of occurrence in Europe. They also live in almost the same types of habitat. However, O. ovalis usually exhibits higher abundance and frequency of occurrence. The major aim of the study was to carry out a comparative analysis of the systematic position, morphological and biological differences, as well as habitat preferences and distribution of O. ovalis and O. karawaiewi. The next aim was to ascertain whether the differences in number and frequency of these species may stem from the genetic differences at the molecular level (16S rDNA and COI). The study shows that O. ovalis, which is a more abundant species than O. karawaiewi, turned out to be genetically more polymorphic.

scholarly journals The importance of non-forest tree stand features for protection of the Syrian Woodpecker Dendrocopos syriacus in agricultural landscape: a case study from South-Eastern Poland

2020 ◽  
Vol 94 (5) ◽  
pp. 1825-1835
Author(s):  
Jerzy Michalczuk
Keyword(s):  
Species Diversity ◽  
Agricultural Landscape ◽  
Habitat Preferences ◽  
Fruit Trees ◽  
Forest Tree ◽  
Health Condition ◽  
Agricultural Landscapes ◽  
South Eastern ◽  
Dendrocopos Syriacus

Abstract Non-forest tree stands are important habitats for many species of birds in the agricultural landscape. They are also the main habitat of the Syrian Woodpecker Dendrocopos syriacus, whose numbers have been decreasing in recent years in some parts of Europe. Recognition of the habitat requirements of this species may help better planning of its protection in the context of the treed agricultural landscapes. During this study, the habitat preferences of the Syrian Woodpecker were determined in the agricultural landscape of South-Eastern Poland. A set of 12 habitat parameters of tree stands located in the breeding territories of the Syrian Woodpecker (n = 122) and in randomly chosen control areas (n = 122) located outside the range of the breeding territories of this species were characterized. The number and species diversity of trees was significantly higher in stands located in Syrian Woodpecker territories than in the random control areas. Stands occupied by breeding pairs also had trees of worse health condition and a larger proportion of fruit trees. The model best explaining the probability of the occurrence of the species indicates that the Syrian Woodpecker requires mainly the presence of tree stands with a greater species diversity of trees, as well as tree stands in worse health condition. When planning the protection of this species’ habitats in the agricultural landscape, the characteristics of non-forest tree stands noted above should be taken into account.

scholarly journals Is there a need for accepting paraphyletic taxa? A case study in the Sardinian endemic Cymbalaria muelleri (Plantaginaceae)

2019 ◽  
Vol 191 (3) ◽  
pp. 325-338 ◽  
Author(s):  
Pau Carnicero ◽  
Peter Schönswetter ◽  
Núria Garcia-Jacas ◽  
Mercè Galbany-Casals
Keyword(s):  
Genome Size ◽  
Phylogenetic Trees ◽  
Fragment Length Polymorphism ◽  
Habitat Preferences ◽  
Molecular Data ◽  
Disjunct Distribution ◽  
Morphological Differences ◽  
A New Species ◽  
The Mediterranean Basin

Abstract Evolution does not always result in dichotomous phylogenetic trees. For instance, in anacladogenetic speciation, where a new species originates by budding, the ancestral taxon is often initially paraphyletic. Here we study Cymbalaria muelleri (Plantaginaceae), a chasmophytic species endemic to Sardinia, a major island in the Mediterranean Basin. Its distribution range is divided into two well-delimited geographical groups with some morphological differences. Using a combination of morphology, molecular data (amplified fragment length polymorphism fingerprinting) and relative genome size, we found that the two geographical groups should be considered two separate taxa, which split through anacladogenesis. Accordingly, we formally describe the new paraphyletic subspecies C. muelleri subsp. villosa as the ancestor, from which C. muelleri subsp. muelleri originated by budding. Morphological analyses support the differentiation of the two subspecies, and there are strong diagnostic characters to differentiate them. In addition to morphology and genetics, slightly divergent habitat preferences and the disjunct distribution of the two subspecies also support the recognition of two taxa. Genome size data obtained for the two subspecies are consistent with the previously established hexaploidy of C. muelleri.

Sign in / Sign up

Export Citation Format

Share Document